French architectural design firms Nicholas Laisné Associés and OXO Architectes have put together a concept for a massive arcology for the Saharan desert. The La Tour des Sables would be a self contained city that rises 1,400 feet above the ground, and would be contain living, agricultural and working units.

Cities are havens for weirdness. From communities built around garbage to dogs that ride the subway, urban environments have fostered all manner of weird patterns. Here are the 10 freakiest urban ecosystems on the planet.

Cities are havens for weirdness. From communities built around garbage to dogs that ride the subway, urban environments have fostered all manner of weird patterns. Here are the 10 freakiest urban ecosystems on the planet.

The fortress-like Kowloon Walled City of Hong Kong was demolished in the early 1990s, but a German documentary crew braved the sprawl in 1989 and captured amazing footage from inside this sunlight-less patchwork metropolis.

Cities are havens for weirdness. From communities built around garbage to dogs that ride the subway, urban environments have fostered all manner of weird patterns. Here are the 10 freakiest urban ecosystems on the planet.

A dystopian megacity, in which buildings merge together to become a single solid block, is the stuff of science fiction — but it already happened, in Hong Kong. The Kowloon Walled City was packed so tightly, it became an arcology.